Unless you're measuring the lift at the outside shell of the lifter with a dial indicator, you're not likely to get an accurate reading. The inside plunger of a lifter can leak down as the engine is rolled over by hand, and yes, if there is actually a 1/16" difference in valve lift, that's far too much variation. When I'm degreeing a cam on a race engine, I substitute a solid lifter for a hydraulic while checking cam timing and lift.
Jerry
